US20190187356A1 - Display device - Google Patents

Display device Download PDF

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Publication number
US20190187356A1
US20190187356A1 US16/227,110 US201816227110A US2019187356A1 US 20190187356 A1 US20190187356 A1 US 20190187356A1 US 201816227110 A US201816227110 A US 201816227110A US 2019187356 A1 US2019187356 A1 US 2019187356A1
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United States
Prior art keywords
light
substrate
light source
display
display device
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
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US16/227,110
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English (en)
Inventor
Ken Hirabayashi
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Japan Display Inc
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Japan Display Inc
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Publication of US20190187356A1 publication Critical patent/US20190187356A1/en
Abandoned legal-status Critical Current

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0013—Means for improving the coupling-in of light from the light source into the light guide
    • G02B6/0023—Means for improving the coupling-in of light from the light source into the light guide provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
    • G02B6/0026—Wavelength selective element, sheet or layer, e.g. filter or grating
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/133553—Reflecting elements
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133617—Illumination with ultraviolet light; Luminescent elements or materials associated to the cell
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/165—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on translational movement of particles in a fluid under the influence of an applied field
    • G02F1/166—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on translational movement of particles in a fluid under the influence of an applied field characterised by the electro-optical or magneto-optical effect
    • G02F1/167—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on translational movement of particles in a fluid under the influence of an applied field characterised by the electro-optical or magneto-optical effect by electrophoresis
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/165—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on translational movement of particles in a fluid under the influence of an applied field
    • G02F1/1675—Constructional details
    • G02F1/1677—Structural association of cells with optical devices, e.g. reflectors or illuminating devices
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/13306—Circuit arrangements or driving methods for the control of single liquid crystal cells
    • G02F1/13318—Circuits comprising a photodetector
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133614—Illuminating devices using photoluminescence, e.g. phosphors illuminated by UV or blue light
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133616—Front illuminating devices
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133624—Illuminating devices characterised by their spectral emissions

Definitions

  • Embodiments described herein relate generally to a display device.
  • Liquid crystal displays are widely used as display devices used for smart phones, tablet computers, car-navigation systems, etc.
  • liquid crystal displays comprise a liquid crystal panel and an illumination device (a backlight or front-light) disposed to be overlaid on a rear surface or a front surface of the liquid crystal panel.
  • the illumination device includes comprises has a light guide, a light source emitting light to enter the light guide, and the like.
  • a white light emitting diode LED
  • the light emitted from white LEDs contains the so-called “blue light”, which is light having a wavelength of 380 to 495 nm.
  • the blue light has properties most close to those of ultraviolet rays, and has such a property that it reaches the retina without being absorbed by the cornea and crystalline lens of eyeballs. Therefore, when the operator sees the blue light for a long time, he or she easily feel eyestrain, which is problematic. Under these circumstances, such a display device has been proposed that a resin layer (blue-light cut layer) to attenuate the blue light is overlaid on a display surface or a rear surface of the liquid crystal panel.
  • the display device it is possible to attenuate the blue light; however, at the same time, the color tone of the display image changes to easily become, for example, yellowish or orange-emphasized, thus, deteriorating the display quality.
  • the present application relates generally to a display device.
  • a display device includes a display panel including a display surface, and an illumination device including a light guide having an emission surface opposing the display surface of the display panel and an incidence surface intersecting the emission surface, a light source configured to emit light entering the incidence surface, and a light cut layer provided between the light source and the incidence surface, to suppress transmission of light having a predetermined wavelength range.
  • FIG. 1 is an exploded perspective view of a liquid crystal display according to a first embodiment.
  • FIG. 2A is a cross section of a light-source side portion of the liquid crystal display.
  • FIG. 2B is a cross section a portion of the liquid crystal display, which is on an opposite side to the light source.
  • FIG. 3 is a plan view schematically showing a light-source side end portion of a light guide and a light source unit.
  • FIG. 4 is a diagram showing a wavelength distribution of illumination light entering the light guide.
  • FIG. 5 is a block diagram schematically showing the liquid crystal display.
  • FIG. 6 is a cross section schematically showing arrangement of the light source and light guide with relative to each other in a liquid crystal display according to a second embodiment.
  • FIG. 7 is a plan view schematically showing a light source-side end portion of the light guide and a light source portion in a liquid crystal display according to the second embodiment.
  • FIG. 8A is a plan view schematically showing a light-source side end portion of a light guide and a light source portion in a liquid crystal display according to a modified example.
  • FIG. 8B is a plan view schematically showing a light-source side end portion of a light guide and a light source portion in a liquid crystal display according to another modified example.
  • FIG. 8C is a plan view schematically showing a light-source side end portion of a light guide and a light source portion in a liquid crystal display according to another modified example.
  • FIG. 9 is a perspective view showing a light source-side portion of a front-light device in a liquid crystal display according to a third embodiment.
  • FIG. 10 is a cross section of the light source-side portion of the liquid crystal display according to the third embodiment.
  • FIG. 11 is a cross section of a light source-side portion of a display device according to the fourth embodiment.
  • a display device comprises a display panel comprising a display surface and an illumination device comprising a light guide comprising an emission surface opposing the display surface of the display panel, and an incidence surface intersecting the emission surface, a light source emitting light entering the incidence surface, and a light cut layer provided between the light source and the incidence surface, to suppress transmission of light having a predetermined wavelength range.
  • FIG. 1 is an exploded perspective view of a liquid crystal display according to the first embodiment.
  • FIG. 2A is a cross section of a light-source side portion of the liquid crystal display device.
  • FIG. 2B is a cross section a portion of the liquid crystal display device, which is on an opposite side to the light source.
  • a liquid crystal display device 10 can be built in, for example, various kinds of electronic devices such as smart phones, tablet devices, notebook personal computers, a handheld game machine, electronic dictionaries, television devices, and car-navigation systems.
  • electronic devices such as smart phones, tablet devices, notebook personal computers, a handheld game machine, electronic dictionaries, television devices, and car-navigation systems.
  • the liquid crystal display device (display device) 10 comprises an active-matrix liquid crystal display panel (to be referred to as “liquid crystal panel” hereinafter) 12 , a front-light device 30 disposed as an illumination device to oppose one of flat surfaces of the liquid crystal panel 12 , that is, a display surface 12 , and a cover panel 14 disposed to be overlaid on the front light device 30 to cover the display surface 12 a and the front-light device 30 .
  • liquid crystal panel active-matrix liquid crystal display panel
  • front-light device 30 disposed as an illumination device to oppose one of flat surfaces of the liquid crystal panel 12 , that is, a display surface 12
  • cover panel 14 disposed to be overlaid on the front light device 30 to cover the display surface 12 a and the front-light device 30 .
  • the liquid crystal panel 12 comprises a rectangular first substrate SUB 1 , a rectangular second substrate SUB 2 opposed to the first substrate SUB 1 , and a liquid crystal layer LQ held between the first substrate SUB 1 and the second substrate SUB 2 .
  • the second substrate SUB 2 is attached by its peripheral portion onto the first substrate SUB 1 with a sealing material SE.
  • a polarizer PL 2 is attached on a surface of the second substrate SUB 2 so as to form the display surface 12 a of the liquid crystal panel 12 .
  • a polarizer PL 1 is attached on a surface of the first substrate SUB 1 (a rear surface of the liquid crystal panel 12 ).
  • a rectangular display area (active area) DA is provided in a region located an inner side surrounded by the sealing material SE as viewing the liquid crystal panel 12 in plan view(, which is, here and hereinafter, a state where the liquid crystal panel is viewed from the normal direction of the display surface 12 a ), and images are displayed on the display area DA.
  • a rectangular frame area ED is provided to surround the display area DA.
  • the liquid crystal panel 12 is a reflective liquid crystal panel which displays images by reflecting external light and the light from the front-light device 30 .
  • the liquid crystal panel 12 may be of a structure provided for either one the lateral electric field mode mainly using a lateral electric field along the surface of the substrate, or the vertical electric field mode mainly using a vertical electric field which intersects the surface of the substrate.
  • the liquid crystal panel 12 comprises a plurality of pixels PX arranged in a matrix in the display area DA.
  • the first substrate SUB 1 comprises, in the display area DA, gate lines G extending in a first direction X, source lines S extending in a second direction Y which intersects the first direction X, switching elements SW each electrically connected to the respective gate line G and the respective source line S in each respective pixel PX, pixel electrodes PE each connected to the respective switching element SW, and the like.
  • a common electrode CE of common potential is provided on the first substrate SUB 1 or the second substrate SUB 2 so as to oppose a plurality of pixel electrodes PE.
  • a pixel circuit PC containing a source line S, a gate line G and a switching element SW, a pixel electrode PE formed of a reflecting electrode, and an alignment film (not shown) are formed on an inner surface of the first substrate SUB 1 .
  • the pixel electrode PE constitutes a reflective film or a reflective layer, which reflects external light and the light from the front-light device 30 .
  • a color filter CF and a common electrode CE formed of a transparent conducting film such as indium-tin-oxide (ITO), and an alignment film (not shown) are provided on an inner surface of the second substrate SUB 2 .
  • a color filter CF and a common electrode CE formed of a transparent conducting film such as indium-tin-oxide (ITO), and an alignment film (not shown) are provided.
  • the liquid crystal layer LQ is enclosed between these alignment films.
  • the liquid crystal panel 12 of this embodiment is a reflective type which displays images by reflecting external light and the light from the front-light device 30 by the pixel electrodes PE.
  • the reflective film does not limited to the pixel electrode, and another reflective film may be provided on the first substrate SUB 1 .
  • the polarizer PL 1 on the rear surface of the liquid crystal display panel may be omitted.
  • a flexible printed circuit (main FPC) 23 is joined to a short-side end portion of the first substrate SUB 1 to extend outward from the liquid crystal panel 12 .
  • the main FPC 23 contains semiconductor devices of a driver IC 24 , an IC chip 25 which constitutes a controller, mounted therein as signal supply sources which supplies signals required to drive the liquid crystal panel 12 .
  • the front-light device 30 is an auxiliary light source which supplies reflection light to the pixel electrode PE when there is no sufficient external light used as a light source, or no external light.
  • the front-light device 30 includes a rectangular light guide LG, a light source unit 34 emit illumination light to enter the light guide LG, a blue-light cut layer (light cut layer) BC provided between an incidence surface of the light guide LG and a light-emitting surface of the light source, a resin frame 40 , and a pair of optical sensors.
  • the light guide LG comprises a first main surface S 1 as an emission surface, a second main surface S 2 opposing the first main surface S 1 , a pair of long-side side surfaces, and a pair of short-side side surfaces. In this embodiment, one of the short-side side surface of the light guide LG is the incidence surface EF.
  • the light guide LG is formed from, for example, polycarbonate or an acrylic or silicon transparent resin.
  • the light guide LG is disposed on the liquid crystal panel 12 while the first main surface (emission surface) S 1 opposing the display surface 12 a of the liquid crystal panel 12 .
  • the first main surface S 1 is attached onto the polarizer PL 2 by, for example, a light-transmissive adhesives or an adhesive AD 1 .
  • the incidence surface EF is located substantially perpendicular to the liquid crystal panel 12 , and extends substantially parallel to the short sides of the second substrate SUB 2 . As will be described later, in this embodiment, a thin film of the blue-light cut layer BC is formed on the incidence surface EF.
  • the light source unit 34 comprises, for example, a belt-like wiring substrate 36 and a plurality of light sources mounted and arranged on the wiring substrate 36 .
  • the light sources light emitting devices, for example, light emitting diodes (LED) 38 are used.
  • LED light emitting diodes
  • white LEDs or pseudo-white LED LED in which a phosphor which glows yellow is disposed on a light-emitting surface of a blue LED
  • the wiring substrate 36 is formed from a flexible printed circuit (FPC).
  • a plurality of LEDs 38 are mounted on the FPC 36 and arranged along the short sides of the first substrate SUB 1 .
  • Each LED 38 comprises a mounting surface 38 b to be mounted on the FPC 36 and a light-emitting surface 38 a located substantially perpendicular to the FPC 36 .
  • the FPC 36 extends along the incidence surface EF.
  • One side edge portion of the FPC 36 is adhered on a light source-side end portion of the second main surface S 2 of the light guide LG by, for example, a double-sided tape TP 1 .
  • Another side edge portion of the FPC 36 is attached on the resin frame 40 by a double-sided tape TP 2 .
  • the FPC 36 is disposed on substantially the same plane as that of the second main surface S 2 of the light guide LG
  • FIG. 3 is a plan view schematically showing the light source-side end portion of the light guide LG and the light source unit 34 .
  • a plurality of LEDs 38 are arranged all along the incidence surface EF at a predetermined gap.
  • the LEDs 38 are arranged in such a state that the light-emitting surfaces 38 a adjacently oppose the incidence surface EF of the light guide LG.
  • the cover panel 14 is formed into a rectangular plate from, for example, a glass plate or an acrylic transparent resin.
  • a lower surface (rear surface, a surface on the side of the liquid crystal panel) of the cover panel 14 is attached on the second main surface S 2 of the light guide LG by an adhesive layer AD 2 made from, for example, a transparent adhesive or tacky agent.
  • the cover panel 14 covers the entire surfaces of the front-light device 30 and the display surface 12 a of the liquid crystal panel 12 .
  • a frame-like light-shielding layer RS is formed on the lower surface of the cover panel 14 .
  • the region of the liquid crystal panel 12 other than the regions opposing the display area DA is shielded by a light-shielding layer RS.
  • the light-shielding layer RS may be formed on the upper surface (outer surface) of the cover panel 14 . Note that the cover panel 14 may be omitted in accordance with the condition where how the liquid crystal display 10 is used.
  • the resin frame 40 of the front-light device 30 is attached on the light-shielding area of the cover panel 14 by, for example, a double-sided tape TP 3 . Further, in the light-source side end portion, the FPC 36 of the light source unit 34 is brought into contact with the light-shielding layer RS while interposing a spacer SP therebetween.
  • the blue-light cut layer BC is formed from a photo-curing resin which is cured by ultraviolet rays or visible light, or a transparent material obtained by mixing a predetermined amount of a coloring material to a base resin of a transparent epoxy resin or the like.
  • the base resin it is preferable to select a type which as an optical transmissivity (to a wavelength of 400 nm or more) after being cured, which is 90% or higher, in order not to lower the optical transmissivity of the light guide LG.
  • the base resin are a monomer, a polymerization initiator, photo-curing resin, a transparent epoxy resin or the like.
  • the coloring material examples include a perylene-based pigment and an azo-based pigment. These coloring materials dissolve in ethyl alcohol at a predetermined concentration, to be mixed with the base resin.
  • a photo-curing resin is used as the base resin and a perylene-based pigment is used as the coloring material
  • the coloring material is dissolved in ethyl alcohol at a ratio of 0.1% by weight, and further mixed into a coloring material solution at 0.1% by weight with respect to the base resin.
  • the resin material is prepared to contain 0.01% by weight of the coloring material with respect to the base resin.
  • the resin material is applied on the entire incidence surface EF of the light guide LG, to form the blue-light cut layer BC.
  • Examples of the application method are dispenser application, slot die-coating, slit coater application, screen printing, and spin coating.
  • the thickness of the coating of the resin material needs to be set according to the concentration of the coloring material mixed to the base resin.
  • the thickness of the coating of the resin material should preferably be about 150 to 250 ⁇ m, and more preferably 200 ⁇ m.
  • the resin material is irradiated with ultraviolet rays in nitrogen atmosphere. In this manner, the resin layer is cured up to its surface, and thus the blue-light cut layer BC can be obtained.
  • FIG. 4 shows spectral characteristics of the illumination light.
  • a solid line indicates the spectral characteristic of the light emitted from the LED 38 and a dashed line indicates the spectral characteristic of the illumination light after passing through the blue-light cut layer BC.
  • a peak value of a light intensity of a wavelength of 380 to 495 nm which is that of blue light, can be reduced by about 25 to 40% as compared to the case where the blue-light cut layer BC is not provided. Therefore, the blue light cut layer BC has a transmissivity to light of a wavelength of 380 to 495 nm of 60 to 75%, and thus a function of suppressing the transmission of blue light, that is, cutting the blue light by 25 to 40%.
  • the materials of the blue-light cut layer BC are not limited to the base resin and the coloring material described above, but may be selected from other various materials.
  • the transmissivity of the blue-light cut layer BC i.e., the blue-light cut rate, is not limited to the value mentioned above, but can be adjusted to arbitrary cut rates by adjusting the concentration of the coloring material.
  • the blue-light cut layer BC is formed to have a uniform thickness over the entire incidence surface EF, but the structure thereof is not limited to this.
  • the blue-light cut layer BC may change its thickness from one place to another, or may be provided in a plurality of locations on the incidence surface EF instead of being formed on the entire surface.
  • the spectral characteristics of LEDs are uniform, but they may vary from one LED to another (dispersion). Therefore, the thickness of the blue-light cut layer BC or the locations thereof may be changed according to the spectral characteristics of each LED.
  • the region opposing LEDs with high blue light intensity may be formed thicker than the other regions.
  • the region opposing LEDs with low blue light intensity may be formed thicker than the other regions.
  • the blue-light cut layer BC may be formed thinner than the other regions, or the blue-light cut layer may be even omitted.
  • a light source-side optical sensor 54 a and an external light sensor 54 b make a pair of optical sensors, and both are formed near a side surface SF which is opposite to the incidence surface EF of the light guide LG.
  • the light source-side optical sensor 54 a is disposed in the state the light-receiving surface thereof faces the side surface SF. That is, the light source-side optical sensor 54 a is provided at a position which opposes the light source (LED 38 ) via the light guide LG.
  • the light source-side optical sensor 54 a receives light from the LED light source, having passed through the blue-light cut layer BC and the light guide LG, and detects the wavelength and intensity of the light.
  • the external light sensor 54 b is disposed in the state the light receiving surface faces the rear surface of the cover panel 14 .
  • the light-shielding layer RS comprises an opening 55 at a position opposing the light-receiving surface of the external light sensor 54 b .
  • the external light sensor 54 b receives external light having passed through the cover panel 14 and detects the wavelength and intensity of the light.
  • the light source-side optical sensor 54 a and the external light sensor 54 b are both connected to a controller 56 , which will be described later.
  • the optical sensors 54 a and 54 b may be configured to detect the wavelength and intensity, or to convert the received light into signal data (RAW data) and then output it to the controller 56 . In the latter case, the wavelength and intensity of each of light rays are calculated by the controller 56 based on the signals.
  • RAW data signal data
  • the liquid crystal display 10 configured as described above, when used in a bright room or outdoor, reflects external light entering the liquid crystal panel 12 via the cover panel 14 and the light guide LG, by the pixel electrode PE of the liquid crystal panel 12 , and displays display images of the liquid crystal panel 12 on the display surface 12 a using the reflection light.
  • the LEDs 38 of the light source unit 34 are turned on and display images of the liquid crystal panel 12 are displayed on the display surface 12 a using the emitted light from the LEDs 38 . That is, the light emitted from the light-emitting surface 38 a of the LED 38 passes through the blue-light cut layer BC, and enters the light guide LG from the incidence surface EF.
  • the blue light component of the incidence light is cut by 25 to 40% with the blue-light cut layer BC.
  • the incidence light propagates inside the light guide LG and is reflected by the first main surface S 2 . Then, it is irradiated from the first main surface S 1 towards the liquid crystal panel 12 .
  • the irradiated light is reflected by the pixel electrode PE of the liquid crystal panel 12 , and the reflection light is used to display the display images of the liquid crystal panel 12 on the display surface 12 a.
  • the blue-light cut layer BC is provided between the incidence surface of the light guide LG and the light source, and thus the blue light component of the illumination light entering the light guide LG from the LEDs 38 is reduced, thereby making it possible to realize image display easy on eyes. Moreover, when displaying images by reflection of external light, the external light does not pass through the blue-light cut layer BC. Therefore, the image display is not affected by the blue-light cut layer BC, or variation in the color tone thereof can be suppressed, thereby maintaining high quality in display. Thus, according to this embodiment, a liquid crystal display which can display images of high display quality while reducing the blue light can be obtained.
  • the liquid crystal display 10 is configured to adjust display images optimally according to the intensity of external light at each wavelength and according to the intensity of the light of the front-light device at each wavelength.
  • FIG. 5 schematically shows an entire configuration of the liquid crystal display.
  • the liquid crystal display 10 includes the display drive circuit 50 which drives pixels of the liquid crystal panel 12 , the light source drive circuit 52 which drives the LEDs 38 of the light source unit 34 , the light source-side optical sensor 54 a which detects the intensity (brightness) of the light of the light source unit 34 at each wavelength, the external light sensor 54 b which detects the intensity (brightness) of the external light at each wavelength, and the controller (controller) 56 which controls the display drive circuit 50 and the light source drive circuit 52 .
  • the display drive circuit 50 which drives pixels of the liquid crystal panel 12
  • the light source drive circuit 52 which drives the LEDs 38 of the light source unit 34
  • the light source-side optical sensor 54 a which detects the intensity (brightness) of the light of the light source unit 34 at each wavelength
  • the external light sensor 54 b which detects the intensity (brightness) of the external light at each wavelength
  • the controller (controller) 56 which controls the display drive circuit 50 and the light source drive circuit 52 .
  • the display drive circuit 50 includes the driver IC 24 , and a gate drive circuit and a signal line drive circuit (not shown), formed on the first substrate SUB 1 .
  • the controller 56 and the light source drive circuit 52 are incorporated in the IC chip 25 on the FPC 23 and are provided next to the driver IC 24 . Note that such a structure is adoptable as well that either or both of the controller 56 and the light source drive circuit 52 are built in the driver IC.
  • the controller 56 turns on or off the LEDs 38 by the light source drive circuit 52 according to the light intensity (brightness) at each wavelength, detected by the external light sensor 54 b .
  • the liquid crystal panel 12 is driven by the display drive circuit 50 to display images without turning on the LEDs 38 .
  • the controller 56 controls the liquid crystal panel 12 to drive at the optimal display state according to the brightness of the external light.
  • the intensity of the blue light is high, that is, for example, light from fluorescent lights occupies the majority portion of the external light, is high, the voltage applied to blue pixels is reduced to lower the optical transmissivity of the blue pixels, and thus the color tone of the entire display image is adjusted.
  • the controller 56 drives the LEDs 38 to be on by the light source drive circuit 52 , and drives the liquid crystal panel 12 by the display drive circuit 50 .
  • the images on the liquid crystal panel 12 are displayed by the illumination light from the LEDs 38 and the external light.
  • the illumination light from the LEDs 38 is detected by the light source-side optical sensor 54 a via the blue-light cut layer BC and the light guide LG.
  • the controller 56 adjusts the RGB display of the liquid crystal panel 12 according to the brightness (intensity at each wavelength) of each type of light, detected by the external light sensor 54 b and the light source-side optical sensor 54 a , thus setting display images of the optimal color tone.
  • the liquid crystal display of this embodiment it is possible to perform the optimal image display according to the external light and the illumination light of the front-light device while reducing the blue light.
  • liquid crystal displays according to other embodiments will be described.
  • structural parts identical to those of the first embodiment described above will be designated by the same reference numbers, and detailed descriptions therefor may be omitted or simplified. Only the different portions from those of the first embodiment will be mainly described in detail.
  • FIG. 6 is a cross section showing a light source-side portion of a front-light device in a liquid crystal display according to the second embodiment
  • FIG. 7 is a plan view schematically showing the light source-side portion.
  • a blue-light cut layer is provided on a light-emitting surface 38 a of each of LEDs 38 .
  • a blue-light cut layer BC is formed by thin film formation on the light-emitting surface 38 a of each of the LEDs 38 , so as to adjacently oppose the incidence surface EF of the light guide LG.
  • the blue-light cut layers BC are formed to have a fixed thickness on the light-emitting surfaces 38 a of all the LEDs 38 , with a common transmissivity.
  • the other structure of the liquid crystal display is the same as that of the liquid crystal display according to the first embodiment described above.
  • a liquid crystal display of high display quality can be obtained while reducing the blue light.
  • the thickness of the blue-light cut layers BC and the locations where they are formed can be changed arbitrarily. As described above, the spectral characteristics of the LEDs 38 may vary from one LED to another. Therefore, the thickness of the blue light cut layers BC and the locations where they should be formed can be selected according to the spectral characteristics of each LED.
  • FIGS. 8A, 8B and 8C are plan views schematically showing light source-side portions of the front-light device according to various modified examples, respectively.
  • the blue-light cut layer BC is not formed for LEDs 38 A, which have comparatively low wavelength intensity of the blue light, of the plurality of LEDs 38 .
  • LEDs 38 A which have comparatively low wavelength intensity of the blue light, are provided with blue-light cut layer BC thinner than those of the other blue-light cut layers BC.
  • LEDs 38 A which have comparatively low wavelength intensity of the blue light, are provided with the blue-light cut layer BC not entirely on their light-emitting surfaces 38 a , but on, for example, only a half area of each.
  • FIG. 9 is a perspective view showing a light source-side portion of a front-light device in a liquid crystal display according to the third embodiment
  • FIG. 10 is a cross section schematically showing the light source-side portion.
  • the front-light device 30 employs a sheet-or film-like blue-light cut layer BC.
  • the blue-light cut sheet BCF is formed by applying a blue light cut layer BC described above on a transparent film.
  • the blue-light cut sheet BCF is disposed between a light-emitting surface 38 a of each LED 38 and incidence surface EF of a light guide LG
  • a blue-light cut sheet BCF is formed into, for example, a belt-like shape and fixed to an incidence-side end portion of the light guide LG.
  • a central portion of the blue light cut sheet BCF along its width direction is tightly attached onto the incidence surface EF, to cover the incidence surface EF.
  • Both edge portions of the blue light cut sheet BCF are bent towards a light guide LG side and are adhered onto end portions of the first main surface S 1 and the second main surface S 2 by double-sided tapes TP 4 and TP 5 , respectively.
  • an FPC 36 of the light source unit 34 is attached to partially overlap a respective side edge portion of the blue light cut sheet BCF.
  • the blue-light cut sheet BCF may be brought into contact with the light guide LG by its film side or blue-light cut layer BC.
  • the other structure of the liquid crystal display is the same as that of the liquid crystal display according to the first embodiment described above. Even when a sheet-like blue-light cut layer is employed as in the third embodiment, a liquid crystal display of high display quality can be obtained while reducing the blue light.
  • the blue-light cut sheet BCF is not limited to the size which covers the entire incidence surface EF, but may be of a size which partially covers arbitrary regions of the incidence surface.
  • FIG. 11 is a cross section of a light source-side end portion of a display device according to the fourth embodiment.
  • a display panel 12 which employs an electrophoretic element is used as a display panel of the display device 10 .
  • the display panel 12 comprises a rectangular plate-shaped first substrate SUB 1 , a rectangular plate-shaped second substrate SUB 2 disposed to oppose the first substrate SUB 1 , and an electrophoretic element 70 held between the first substrate SUB 1 and the second substrate SUB 2 .
  • the second substrate SUB 2 is attached by its peripheral portion onto the first substrate SUB 1 by a sealing material SE.
  • a barrier layer BA 2 is attached on a surface of the second substrate SUB 2 , to form a display surface 12 a .
  • a barrier layer BA 1 is attached on a surface (rear surface of the display panel 12 ) of the first substrate SUB 1 .
  • pixel circuits PC including source lines, gate lines, switching elements, and pixel electrodes PE formed of reflecting electrodes are provided.
  • the pixel electrodes PE constitute reflective films or reflective layers provided on the first substrate SUB 1 .
  • a common electrode CE formed of a transparent conducting film such as of ITO, is provided on an inner surface of the second substrate SUB 2 .
  • the electrophoretic element 70 comprises a number of microcapsules 60 dispersedly arranged on substantially an entire area between the first substrate SUB 1 and the second substrate SUB 2 .
  • the electrophoretic element 70 can as well adopt, for example, a sheet type comprising a pair of films formed from a transparent resin and disposed to oppose each other, and microcapsules dispersedly arranged between these films.
  • the microcapsules 60 have a particle diameter of, for example, about 50 to 100 ⁇ m.
  • the microcapsules 60 each comprise a spherical outer shell 62 , a plurality of white particles (electrophoretic particles) 60 a , a plurality of black particles (electrophoretic particles) 60 b and a dispersion medium 64 , contained in the outer shell 62 .
  • a dispersion medium 64 contained in the outer shell 62 .
  • one or more microcapsules 60 are formed in a region opposing one pixel electrode PE.
  • the microcapsules 60 are dispersed arranged over the entire display area DA.
  • pigments of red, green, blue, yellow, cyan, magenta or the like may be used.
  • red, green, blue, yellow, cyan, magenta and the like can be displayed on the display surface 12 a .
  • particles of one of the above-listed colors are provided in microcapsules in addition to the white particles and black particles.
  • the display panel 12 is attached onto the first main surface S 1 of the light guide LG with, for example, a light-transmissive adhesive or adhesive AD 1 .
  • the other structure of the display device which includes, for example, a front-light device 30 and a cover panel 14 , is the same as that of the liquid crystal display according to the first embodiment described above. With the fourth embodiment as well, a liquid crystal display of high display quality can be obtained while reducing the blue light.
  • the LEDs are not limited to a side view type, but top-view LEDs may as well be used.
  • the LEDs are not limited to white light LEDs, but those emitting colors of RGB may as well be used.
  • the light emission of the front-light device is controlled according to the intensity of external light at each respective wavelength, thereby making it possible to adjust the color tone of display images.

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11415829B2 (en) * 2020-08-10 2022-08-16 Tcl China Star Optoelectronics Technology Co., Ltd. Liquid crystal display panel and liquid crystal display device
US11556030B2 (en) 2021-03-29 2023-01-17 Japan Display Inc. Liquid crystal display device

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112946947B (zh) * 2021-02-07 2022-10-25 捷开通讯(深圳)有限公司 反射型液晶显示屏及其制备方法、显示装置
CN112764272A (zh) * 2021-02-09 2021-05-07 捷开通讯(深圳)有限公司 显示模组及显示装置
CN117250789A (zh) * 2023-09-06 2023-12-19 深圳市海思通光电科技有限公司 一种带有防蓝光功能的智能ips护眼显示屏

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050266176A1 (en) * 2004-05-27 2005-12-01 Alps Electric Co., Ltd. Anti-reflective structure, anti-reflective film having the same, light guide, illumination device, and liquid crystal display device
US20100109003A1 (en) * 2008-10-31 2010-05-06 Semiconductor Energy Laboratory Co., Ltd. Semiconductor device and method for manufacturing the same
US20100188322A1 (en) * 2009-01-26 2010-07-29 Norimasa Furukawa Color display unit
US20160091651A1 (en) * 2014-09-29 2016-03-31 Wistron Corporation Backlight module and display having the same

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050266176A1 (en) * 2004-05-27 2005-12-01 Alps Electric Co., Ltd. Anti-reflective structure, anti-reflective film having the same, light guide, illumination device, and liquid crystal display device
US20100109003A1 (en) * 2008-10-31 2010-05-06 Semiconductor Energy Laboratory Co., Ltd. Semiconductor device and method for manufacturing the same
US20100188322A1 (en) * 2009-01-26 2010-07-29 Norimasa Furukawa Color display unit
US20160091651A1 (en) * 2014-09-29 2016-03-31 Wistron Corporation Backlight module and display having the same

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11415829B2 (en) * 2020-08-10 2022-08-16 Tcl China Star Optoelectronics Technology Co., Ltd. Liquid crystal display panel and liquid crystal display device
US11556030B2 (en) 2021-03-29 2023-01-17 Japan Display Inc. Liquid crystal display device

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